Currently measurement of machinery wear by detection of wear debris involves removal of oil samples from the machinery for analysis by use of magnetic Hall effect sensors, which may be intrusive and./or very expensive, where fiber optics types of such sensors are utilized. Other generally known optical fiber systems for monitoring metallic debris require algorithms to discern the metallic debris from air bubbles and other anomalies. It is an important object of the present invention to provide a relatively smaller and less intrusive system for the detection and measurement of metallic debris reflecting machinery wear.